Process of making silicon tetrachlorid



R. w. MOORE. PROCESS OF MAKING SILICON TETRACHLORID.

APPLICATION FILED FEB. I8. I918.

' Patented Aug. 24, 192

Outlet- I [n/ez,

. Inventor; Rog W. Tfloore,

Hus fittorneg A UNITED STATES PATENT. OFFICE.

ROY W. MOORE, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

PROCESS OF MAKING SILICON TETRACHLORID.

Specification of Letters Patent. Patented Aug, 24, 1920.

Application filed February 1a, 1918. Serial No. 217,740.

T all whom it may concern:

Be it known that'I, ROY W. 'Moonn, a citizen of the United States, residing at Schenectady, county of Schenectady, State 5 of New York, have inventedcertain new and useful Improvements in Processes of Making Silicon Tetrachlorid, of which the following is a specification.

The present invention relates to the control of exothermic chemical reactions between substances 011 a scale large enough to cause sufficient rise of temperature in the reaction mass to yield undesired reaction products unless the formation of such products is guarded against.

My invention is particularly-applicable to the eflicient production of fluid reaction products, such, for example, as halogen compounds of silicon, boron, titanium, and the like, by combination of the respective metalloid, or of a compound, for example the carbid, with a halogen 'such' as chlorin 0r bromin. For example, when silicon tetra chlorid is made by conducting chlorin gas into contact with heated silicon and the amounts of silicon and chlorin are suffifciently great, the colorless silicon tetraehlorid becomes contaminated with a brownish yellow solid compound, which appears to be a 'subchlorid of silicon. This compound, v

I have discovered that the reaction may be carried out unimpeded with an. unrestricted yield by controllably withdrawing heat from 40 the reaction zone to prevent the formation of the undesired compound or compounds.

The novel features of my invention are pointed out with greater particularity in the appended claims, and for a better understanding of my invention reference may be Y had to the accompanying description taken.

in connection with the accompanying drawing which shows a side elevationwith parts partly brokenaway of a simple apparatus for carrying out my invention.

Referring to the drawing the charge of silicon, silicon carbid, titanium carbid, or

other material which is to take part in the reaction with the halogen is placed in the comminuted state in a container 1 which may consist of copper, or other suitable metal. The container 1 is located within a tank 2 containing a cooling fluid, preferably water, introduced by an inlet tube 3 having a valve 4 and an outlet tube The reaction chamber has a charging throat (S projecting above the water level closed by means of a stopper 7, through which passes the tube 8 for introducing the halogen. This tube 8 is connected to a suitable source of supply. A valve 9 serves to regulate the flow of gas through the gas-conveying tube. The apparatus may be supported by pedestal l0 and communicates through a tube 11 with a tank 12 for receiving the silicon chlorid, or other into contact with the moisture of the atmosphere.

The reaction may be started when the apparatus has been suitably charged with silicon, silicon carbid, or the like, by heating some of this material externally in a' crucible and then introducing it into the reaction chamber on top of the char e and immediately starting the stream of c lorin,

or the like. An exothermic reaction 'takes place which heats the rest of the charge whereupon the stream of chlorin gas is suitably regulated by means of the valve 9 to have the reaction take place at the desired rate. The rate of reaction may be rapid enough to furnish. a continuous stream of liquid silicon tetrachlorid or other reaction product into thetank 12 without danger of the metal container 1 being attacked chemically or that a brownish, yellow subchlorid will be formed. In the case ofthe reaction between chlorin and titanium carbid to form titanium'tetrachlorid, an undesired reddish brown compound is formed in case the reaction temperature is allowed to become too unless the'reaction temperature were con- 35 high.- If heat is not removed by I medium, the reaction is likely to run away with the accompanying production of un sired reaction products.

Preferably the container 12 consists of glass so thatthestream of material coming from the tube 11 may be observed and if it is noticed that there is a little solid product coming through from the chamber 1, the cir-- *culation of the cooling water may be increased somewhat or the temperature of the cooling water lowered, or both, in order to more vigorously cool the reaction chamber. Ordinarily it will not be necessary to restrict the inflow of the chlorin, or other halogen through the tube '8 into the reaction chamber. The effect of the'cooling in the control of the present reaction therefore very materially increases the efficiency at which the apparatus may be operated and increases therrateat whichthe desired halogen product may be formed without forming an undesired solid sub-halogen product.

While I have made claim particularly to a process of making silicon tetrachlorid from a charge containing silicon as a constituent, that is, a charge either of silicon or a compound of silicon, such a .silicon carbid, I intend by these claims to also cover the process of making compounds of other elements, such as titamum, which form-more than one halogen compound and which would form mixtures of halogen compounds a cooling trolled.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. A step in the process of carrying out a reaction between a halogen and a charge containing silicon as a constituent, which consists in controllably withdrawing heat from the reaction zone to maintain the reaction temperature within the range in which a desired silicon compound is formed and below the point at which undesired halogen compounds of silicon are'formed.

2. The process of making silicon tetrachlorid by combination between silicon and chlorin in quantities sufliciently great to produce undesired reactions products which I formed.

In witness whereof, I have hereunto set my hand this 15th day of February, 1918.

ROY W. MOORE. 

